Reaction mass of 4,4'-isopropylidenediphenol and phenol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

BOD-test following "Standard methods for the Examination of water and wastewater" (Am. Pub. Health Assn.)

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

other: settled domestic waste water and mixture of seawater/wastewater, resp., inoculum non-adapted

Details on inoculum:

Freshwater:
settled domestic wastewater (3 ml/bottle)
seawater
the seed used was developed in seawater taken from Lavaca Bay (Texas), the seed was mainted by adding small
amounts of settled raw wastewater every 3 to 4 days as a source of substrate, seed bacteria, and growth factors

Duration of test (contact time):

20 d

Initial conc.:

>= 3 - <= 10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to standard method
- Additional substrate:


TEST SYSTEM
- Culturing apparatus: BOD bottles
- Number of culture flasks/concentration: duplicate bottles per test concentration; at least two test concentrations of three (3, 7, 10 mg/L)


SAMPLING
- Sampling frequency: day 0 and every 5 days

freshwater test: BOD bottles were half filled with aerated dilution water and settled domestic waste water (3 mL/bottle) was added
containing minerals and buffer; concentrations of TS: 3, 7, and 10 mg/l; at least two of the concentrations were tested
in duplicate; the bottles were reaerated, when the DO dropped below 4.0 mg/l

seawater test:
the biodegradation was carried out in synthetic seawater; concentration of TS: 3, 7, and 10 mg/l; at least two
concentrations were tested in duplicate; the bottles were reaerated, when the DO dropped below 4.0 mg/l

Parameter:

% degradation (O2 consumption)

Value:

96

Sampling time:

20 d

Remarks on result:

other: freshwater, non-adapted

Parameter:

% degradation (O2 consumption)

Value:

86

Sampling time:

20 d

Remarks on result:

other: salt water, non-adapted

Details on results:

Kinetic of test substance (in %):
fresh water:
= 90 % after 5 days
= 89 % after 10 days
= 87 % after 15 days
= 96 % after 20 days

salt water:
= 55 % after 5 day(s)
= 74 % after 10 day(s)
= 78 % after 15 day(s)
= 86 % after 20 day(s)

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Degradation of phenol was tested in fresh water and salt water applying the published BOD procedure. Non-adapted inoculum was applied.
The results show > 70 % biodegradation for fresh and salt water within the first 10 days indicating ready biodegradability of phenol.

Executive summary:

Degradation of phenol was tested in fresh water and salt water applying the published BOD procedure. Test substance was added as sole carbon source. Degradation was followed by the oxygen decrease in the test mixture incubated in sealed test vessels. Non-adapted inoculum was applied. For the fresh water test settled and filtered domestic waste water was used as seed. For the seawater biodegradation test the seed was maintained by adding small amounts of settled raw wastewater about every 3 to 4 days to seawater taken from the environment.

Duplicate test vessels were analysed per test concentration and sampling time. The results show > 70 % biodegradation for fresh and salt water within the first 10 days indicating ready biodegradability of phenol.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Method of cultivation: semi continously cultured by the MITI method with a synthetic sewage
- Pretreatment: no

Duration of test (contact time):

10 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: K2HPO4 25.75 g/L; KH2PO4 8.5 g/L; Na2HPO4 * 12 H2O 44.6 g/L; NH4Cl 1.7 g/L; MgSO4 * 7 H2O 22.5 g/L; CaCl2 27.5 g/L; FeCl3 * 6 H2O 0.25 g/L
- sludge: 30 mg/L; the sludge for the seeding had been semicontinuously cultured by the MITI method with a synthetic sewage of the following compostion: Glucose 25 g/L; Peptone 25 g/L; corn steep liquor 16 mL/L; KH2PO4 25 g/L; NaOH 16 g/L
- Temperature: 20 °C

TEST SYSTEM
- Measuring equipment: electrolytic respirometer

Parameter:

% degradation (O2 consumption)

Value:

62

Sampling time:

100 h

Details on results:

phenol concentration t1 (lag phase) k t[h] (degradation time) BOD/ThOD DOCd/DOC0
(mg/l) (h) (h-1) (h)
100 20 0.028 100 0.62 0.09
30 15 0.037 90 0.70 0.06
10 15 0.041 90 0.60 0.07

Results with reference substance:

no information

no further information

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

After a test period of 100 h, phenol (100 mg/L) resulted in a degradation rate of 62 %. The lag-phase was 20 h. Therefore, phenol is classified as readily biodegradable.

Executive summary:

The biodegradability of phenol (100 mg/L) was investigated in a ready biodegradability test (MITI). Activated sludge cultured in the laboratory was applied. Phenol was degegraded to 62 % within 100 h. The substance can be classified as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The environmental properties of the reaction mass of phenol and 4,4’-isopropylidenediphenol was assessed by examination of the properties of the constituents and impurities of the mixture and using this information in a read across approach as described in section 13. 

 

The major constituents of the reaction mass, namely phenol and 4,4’-isopropylidenediphenol (representing 60-85% of the composition) have been shown to meet criteria for classification as readily biodegradable. Phenol showed 62% biodegradation within 100 hours in the OECD 301C screening test. Extensive biodegradation (86-96%) was also noted for phenol in biochemical oxygen demand tests conducted with both freshwater and saltwater inocula. 4,4’-Isopropylidenediphenol has also shown to be extensively degraded in OECD 301F manometric respirometry tests. The extent of degradation ranged from 77 to 92.3% and 76 to 81% based on oxygen consumption and CO2 formation, respectively.

 

Biodegradation of the impurities in the substance was assessed using both QSAR estimation and experimental methods. Screening tests were conducted according to OECD 301F with a test material, 2-Acetone, polymer with Phenol, which is a suitable surrogate for the reaction mass of phenol and 4,4’-isopropylidenediphenol. The results showed 16% biodegradation after 28 days, although biodegradation may have been limited by availability of the components to the microorganisms. QSAR model predictions indicate the various minor constituents of the reaction mass are expected to biodegrade slowly and at varying rates, ranging from weeks to months. Overall, the substance (reaction mass of phenol and 4,4’-isopropylidenediphenol) would be expected to ultimately biodegrade in the environment.